Traffic-signal controller



June 27, 1939. B. w. JONES 2,164,177

TRAFFI C S I GNAL CONTROLLER Filed June 24, 1936 2 Sheets-Sheet l N Fggl.

Inventor: Benjam in W Jones,

' I .10 WWcSJW His Attorne g,

June 27, 1939. v a ONES 2,164,177

' TRAFFIC-SIGNAL CONTROLLER Filed 'June 24, 1956 2 Sheets-Sheet 2 r Fig.5.

Inve ntor: Benjamin W..Jo nes,

by, F His Zbtorney.

Patented June 27, 1939 PATENT (OFFICE TRAFFIC-SIGNAL CONTROLLER.

Benjamin W. Jones,

New Yorlr Schenectady, N. Y., assignor to General Electric Company,

a corporation of Application June 24, 1936; Serial No. 86,909

8 Claims.

to trafllc-signal apparatus, to vehicle-actuated traflic lll For a better understanding of my invention,

together with other and further objects thereof,- reference is had to the following description, talren in connection with the accompanying drawinns, and its scope will be pointed out in the appended claims.

in the accompanying drawings, Fig. l is a diagrammatic illustration oi a street intersection equipped with a tramc signal and actuating switches in the path of each vehicle lane; Fig. 2

is a sectional view, talren parallel to the axis oi? the road, oi my improved vehicle tuat switch; Fig. 3 is a schematic diagram oi a controller built in accordance with my invention, Fig. t isa mod ihcation thereof and Fig. his arearrangement oi as the diagram of Fig. 3 illustrating a common polit tive and a coon negative conductor ior all'the elements of the controller. Referring to the drawings in det, Fig. 1 illustrates a trams signal it mean in the center 7 oiftwo intersecting streets running respective-1i? north and south and east and west. Vehicleactuated devices, such asswitches ll, l2, l3 and lt,'operable by vehicles, are placed on the approach side of each vehicle lane. The switches I I and I! are in the El-W. street and are conne in multiple; withleach' other. The switches" 13'" and it are mine-ma and are-connected in multiple so that when the right of waylls obtained for either 'street the right .01 way is ior both 40 directions inthatstre'eh: InFig. 2, a sectional v l takefi W3 the a ds of the was, of m -i proveawnma actuated switch is illiistratedfi This switch prises a .body II ot-faresilientgmaterlalfsuchfas the street page rubber for example, ment It. Contacts "and; ll are embedded in the resilient body II and are separated by a terial H which may be, for example, .commiriuted. carbon which will normally be partially con ductive, but becomes increasingly conductive upon the application of pressure due to the weight of the vehicle passing thereover. With this arrange- V ment it is possible to actuate a relay at the in- 55 stant that the vehicle rides over the switch and "a shaft not shown.

arcuate space oi approximately 30,

. suillcient length to close .Ithe segments 30) ,o' 32, or are radially spaced so that their centers line up 7 I with the centers of the segments 33, 34, and 35. o'-

oij the relay 21'. I with each other and by conductor 41 to'contact 43 of the relay 25.

to hold this relay in that position after the vehicle has passed.

Fig. 3, as above stated, is a schematic diagram of a traffic-signal controller built in accordance with my invention. It includes a pair of' rotary d timingrswitches 2i and 22 operated respectively by motors 23 and 2t. Vehicle-actuated switches ill-l2 and lt--l t operate respectively relays 2h and 2h. The relays 25 and 26, together with timing switches 2 l' and 22, operate a signal-chang ing relay ii for energizing signals 2t and 2t which, when energized respectively, grant the right oi? way to the N.-S. and E.-W intersecting tramc lanes respectively.- The motors 2i and 2d are preferably self-starting synchronous motors, so that their speed is dependent upon the frequency of the available current'source and, therelorejpredetermined for any constant frequency;

liimlng switch it comprises a rotating arm til which is connected 'to the positive side of a curan rent source and is rotated by the motortt through The arm it engages several of concentrically-arranged contacts during its movent' The inner contact 3|! is a continuous contact broken only at the top for an at The second or intermediate series of contacts includes contacts tt iit, hi, it and 36, which are equally sd about the center of the switch, each contact being approximately 50 in length. The third, and outside, series of contacts 31!, 33, 3d and it are somewhat shorter than the interme- I series of contacts. Contact 31 is spaced above the gap in contact 3! and also above the space between the contacts 32 and 36. It is of 85 Y this gap so that the arm "engages this segment before it'leaves either of 36. Contacts 33, 39 and lime contact 3i isconnected by conductors 4| and I {to contact 43 of the signal changing relay 21. Thetjcon'tactst 32 to 36 are connected with each ""r ahd by conductors H and I5 to contact 45 Contacts 31 to are connected The timing switch 22 is similar in construction to switch 2i. It is provided with a rotating arm 49 connected to the ground sideoi a current 50 source. It is-provided with a stationary contact- 50 corresponding to the contact 3| of switch 2|, contacts 5l, 52, 53, Stand corresponding respectively to-contacts 32 to 36 and contacts 56,

"51, 58 and 59 corresponding respectively to con- 55 tacts 31 to 43 of the switch 2|. The contact 53 is connected by conductors 53 and 5| to contact 52 of the relay 21. The contacts 5|, 52, 53, 54 and 55 are connected to each other, and by conductors 53 and 54 they are connected to contact 35 of the relay 21. The contacts 55, 51, 53 and 53 are connected to each other and by conductor 33 to contact 51 of relay 25.

' The above circuits are so arranged that, when no vehicles cross the intersection the right-ofway indication remains in the street which last had it. This same condition holds when vehicles travel only in this one street. When vehicles approach in an intersecting street the actuation of the vehicle switch in this street energizes the motor of the timing switch corresponding to this vehicle switch and the rotating arm thereof is moved relatively to the stationary contacts at a predetermined speed.

In Fig. 3 the relay 21 is illustrated as being in its lower position in which signal 23 is energized granting the right of way to the E.-W. lanes. The signal circuit may be traced from contact 53 which is connected to the positive side of a source, through movable contact bar 53 of relay 21, contact 10, conductor 1| to signal lamp 23 and conductor 12 to ground. A circuit may also be traced to motor 23, from the contact 53, to contacts 33 and 43, conductors 42 and 4| to motor 23 and ground. The arm 33 is, therefore, rotating clockwise at this time. If, during this condition of the circuits vehicles operate the E.-W. switches ||-,-|2, the relay 25 will be energized only at intervals during which arm 33 traverses the intermediate contacts 32 to 33. When arm 33 is between any two of these contacts, the relay 25 remains in the position illustrated.

Assuming'now a car approaching on the N.-S. street and passing a vehicle switch l3 or M. A circuit will be established from the positive side of a source through the coil 13 of the relay 23, conductors 53 and 34 to contact 55 of relay 21 and through the movable contact bar 14 to the stationary contact 15 which is connected to ground. A circuit is thereby established through the relay coil 13 which lifts its moving contact 13 and thereby establishes a circuit across the two upper contacts 11 and 13 As stated above the material l3 between the contacts of the vehicle switches is partially conductive. For this same reason picked up, vehicle wheel does not remain on the switch, and remains so until the circuit is broken elsewhere.

When, after the relay 23 picks up, a condition of the apparatus is obtained wherein the relay 23 is deenergized and the rotating arm 33 is in engagement with one of the contacts 31 to 43, a circuit is established whereby relay 21 is operated.

This circuit may be traced from the positive sideof the source to which the arm 33 is connected, through the arm 33, contact 31, conductor. 41, contacts 43, 13 and 33 of relay 25, conductor 3| contacts 13, 13 and 11 of relay 23, conductor 32, resistor 33, conductor 34, relay coil 33 to ground. The relay 21 is thereby energized to move its contacts to their respective upper positions. As a result thereof the circuit through signal 23 is broken and a circuit through the signal 23 is established as i'ollows: From the positive side of the current source through contacts 33, 31 and 33 of the relay 21, conductor 33, signal 23 and conductor 12 to is established ground. Simultaneously a circuit through the motor 24 and timing lay 25 from ground through the of the relay 25.

the relay, when remains in that position although the switch 22 begins to operate. This circuit may be traced from grounded contact 33, movable contact 9|, contact 32, conductor 5| motor 24 to the positive side of the source. The circuit to motor 23 through the contacts of relay 21 is broken, but the motor continues to operate until the arm 33 leaves contact 3| through which it receives current. This circuit may be traced from the positive side of the source to arm 33, contact 3|, conductor 4|, motor 23 to ground.

The arm 43, of timing switch 22, begins to rotate as soon as the relay 21 contacts are moved upwardly. The arm moves clockwise and engages contacts 50 and 5| before the relay 25 drops to its lower position. During the time arm 43 engages contact 50, the motor 24 receives current irrespective of the position of relay 21. The circuit may be traced from ground to arm 43, contact 50, conductor 60, motor 24 to the positive side of the source. When the motor of the timing switch is started, therefore, it continues to operate for a complete revolution. As long as arm 43 engages one of the contacts 5| to 55, a circuit through reis established and it holds its contact 15 in the upper position. This circuit may be traced from arm 43, contacts 5| to 55, conductor 53, relay coil 13, switch l3 or M to the current source. The contacts 5| to 55 are, however, only some 50 long having 22 spaces between. Therefore, when the contact arm 43, during its movement, leaves one of these contacts, the circuit to relay 25 is broken and cannot be reestablished until another one of this group of contacts is reached, the purpose of this being that unless cars continue to operate the switches l3 and H, the relay is deenergized to enable cars in the intersecting streets to obtain the right 01- way.

Assuming, therefore, that one vehicle caused the change of right of way as just described and that a vehicle inthe E.-W. street actuated switch H or 2 during the time arm 43 was in engagement with contact 5|. When the switch H or |2 was operated a circuit through the corresponding relay 25 was established. This may be traced switch II or |2, relay 45, contacts 43, 31 and The relay, therefore,

coil 32, conductors 44 and 33 to the current source. raises its movable contact 13 to engage contacts 33 and- 34. This does not change the signal setting, however, as long as relay 23 remains in its upper position. When relay 23 does drop to its lower position, due to arm 43 moving ofl contact 5|, an operating circuit to the signal relay 21 is established as soon as arm 43 reaches the outside segment 51. This circuit may be traced from grounded arm 43, contact 51, conductor 33, contacts 31, 13 and 35 of relay 23, conductor 33, contacts 34, 13 and 33 of relay 23, conductor 31, resistor 33, conductor 34 to coil 33 and to the current source. The completion of this circuit energizes the coil 33, and since the circuit to coil 33 was broken when the relay 25 picned up its contacts, the coil 33 is deenergized and the coil 33 moves the relay contacts 21 back to the position shown in the drawings.

From the foregoing description it isevident that the length of an intermediate contact segment, such as 3|, and the distance from this contact to the next outside contact, such as contact 51, determines the time period for which a single car may retain the right of way if a vehicle appears at the intersection in another of the intersecting'streets and no other vehicle appears on the street having the right of way. If such other car does appear on the intersecting street, the sigon E.-W.' street.

2,104,177 ,nals are changed to transfer the right oil way to thisvehicle on the intersecting street at the end of this period and it retains the right of way for a similar period. If, on the other hand, a second vehicle appears on the intersecting street before this minimum period has expired the signals can be held in the existing condition for another similar period. Assuming now street "E.-W. having the right of way, that a vehicle appears'on N.-S.

street before the minimum period for E.-W. has expired and that a second vehicle also appears As above explained, relay 26 would pick up its contacts responsive to the 'vehicle in N.-S. street. If nothing else happened, the circuits above described would be established and relay 2! would shift its contacts when arm 36 engaged one of the contacts 3'I-'to 46. The

vehicle on E.-W. street, however, in accordance. with our assumption, raised relay assoon as arm 36 engaged contact 33. This arrangement of contacts is such that the space between contacts 32 .and 33 is suflicien't to instantaneously drop the relay 25 and to permit its pick-up by an actuation'ofvehicle switches I I or I2 before, an outside contact, such as 38 is engaged by the arm 36.- If .such vehicle actuation does take place the previous actuation of relay 26 in the intersec g street is of no consequence since the relay 26 merely breaks the circuit which would otherwise be established to the operating coil-66 of relay 21. Thiscircuit may be traced from the arm 36, contact 36, conductor 61, relay contacts 46, I6 and 86, conductor 8| contacts I616'I'I, conductor 62,'resistor 83, conductor 64 and coil 65.

The establishing of this circuit, as already explained, would operate the'relay 2I toits: upper position and thereby change the. signals.

Because of the second operation of relay 25, the

vehicle which operated the relay 26 is madeto wait another timeperiod equivalent to the move ment ofthe arm 36 over the'contact 33'and the additional movement necessary to engage contact 39. When the arm 36- leaves contact 33, the relay 25 is dropped. The energynecessary to operate the signal changing relay 21' is not obtained, however, until a time period -later when arm 36 engages contact 39. Ifin the meantime relay 25'was again operated, the circuitagain remains broken until arm 36 leaves contact 34.

The process may further be repeated for the time period necessary to traverse contacts 35 and 36. When the arm 36 leaves contact 36, however, it immediately engages the contact 31 and establishes the circuit necessary to operate relay 21 and thereby change the right of way to the waiting vehicle. The space between contacts 36 and 32 is for this reason made-greater than between others of this series of contacts. Simultaneously the motor 23 is deenergi'z ed by arm'36 leaving contact 3|.

When the rightof'way isgiven to the waiting vehicles on the N. -S.- street, the control of the time period allotted vests in the rotating arm 46..

If'subsequently another vehicle appears on the N38. street tomove relay 26 to its upper position, as above described for relay 25 in the E.-W. street. and if by repeated actuations of the vehicle switches I3 and I4, the relay-remainsin this upper position, the right of way remains on the N. -S. street for a maximum period equivalent to the time necessary to rotate the switch arm I! for a complete revolution. Y 3 v From the above description it isevident'that' a full automatic operation of traflic signals may be obtained with simple apparatus. The time periods are easily adjusted by regulating the time for a single revolution of the switch arms 46 and 46 and by regulating. the length of the contact segments. The length of each intermediate segment determines the time period given ,for a single vehicle to cross the intersection. In order to givea waiting vehicle in the other street -the period, between the end of the minimum period and the engagement of an outside cog"- tact, th'e first vehicle relay may again be lift d and thus retain the right of way for another minimum period. This process can be repeated until amaximum time is reached after which the flow of traiiic in the first street is stopped and the right of way is given to the waiting vehicle.

In this second street the process is repeated. The right of way is again held only as long as vehicles operate the switches and corresponding relay and, if that is the case, then it can be done only for a predetermined maximum period.

.The signals 26 and 29 may be of any desired type. The preferred type comprises a. lamp orI group of lamps energized to give a positive right of way.indication to one street and a positive stop indication to the intersecting streets. These indications are usually a green lens for the Go indication and a red lens for the "Stop indica- I tlon. A change of signal warning may be used comprising a "yellow signal which is energized for a short period before each signal change.

Such warning signal may be incorporated in any convenient manner, for example, by incorporat ing a time delay device in the signal circuit which will energize the warning light at each change of the signal relay before energizing the stop and go signals. .An example of such caution indication is illustrated in Fig. 4. Any other of thewell-known arrangements now in use may be incorporated, however, in this system. I In Fig. 4, I have illustrated a time delay device I66 connected into the conductor 89. The time delay device I66 comprises a magnet coil I6I, a

movable contact I62 and a time delay device I63,'

such as the well-known dash pot. When the coil its lower position where it completes a circuit "from conductor 86 through coil I6I, contact I62.

conductor I66 to a caution signal I65, which may be equipped with lenses colored orange or yellow.

'When conductor is energized, due to the action of relay 21, the caution light is energized for a time period regulated by the device I63. When this period expires the contact I62 moves to its I6I:is deenergized the movable contact I62 is in upper position and engages an upper set of contacts, thereby establishing a circuit to the signal 26. The coil III remains in series with this circuit and holds contact I62 in this position until the current flow to conductor 69 is interrupted.

In Fig. 5, the elements of Fig. 3 are arranged 'between'a common positive conductor I66 and the common grounded conductor 12. This type 70 J of diagram is considered, ior some purposes to be clearer than the diagram at Fig. 3. In order to keep the diagram in its simplest form, the elements illustratedin Fig. 3 are slightly rearranged,

and each of the conductors terminating in a ground indication or in a plus indication is carried to the respective positive and negative conductors running vertically along the opposite sides of the diagram. In arranging the elements to suit this diagram, it is necessary to make one change in the arrangement of the two pairs of contacts operated respectively by the relays 25 and 26. In Fig. 3, the relay 25 operates contacts 93-94 and 49-80, the latter being normally closed, and relay 26 operates contacts "-18 and 66-95, of which 95-95 are normally closed. In rearranging the diagram to suit the requirements of an across-the-line diagram", it

was found that the same operating result can be obtained by having relay 25 operate contacts "-18 and 93-94, of which ll-l8 are normally closed, and to have relay 26 operate contacts 48-90 and 61-95, of which 61-95 are normally closed. With the above arrangement of the contacts, a complete circuit to one of the coils of relay 2'! is obtained when either of the two relays 25 is actuated. This results in exactly the same operation as illustrated in Fig. 3

What I claim as new and desire to secure by Letters Patent of the United States is:

1. In a traffic-signaling system, the combination of signals operable to indicate the right of way to several intersecting streets successively and for simultaneously indicating stop to the others, a signal switch operable to, several positions to energize the necessary signal combinations in each of its several positions respectively, vehicle-actuated devices in each of said streets, and timing switches operable respectively responsive to actuations of said vehicle-actuated devices inthe intersecting streets to control the positioning of said signal. switch and for maintaining said signal switch in a selected position for a minimum time period responsive to a single actuation of a vehicle-actuated device.

2. In a traflic-signaling system, the combination of signals operable to indicate the right of way to several streets successively and for simultaneously indicating stop to the others of said streets, a signal switch operable to several positions to energize the signal combinations in each of its several positions granting the right of wayv to said intersecting streets respectively, vehicle-actuated devices in each of said streets, and timing switches respectively responsive to actuations of said vehicle-actuated devices to operate said signal switch to assume a predetermined position responsive to an actuation of a vehicle-actuated device in one of the intersecting streets, to hold said signal switch in said position for a predetermined minimum time period and to hold said signal switch in said position for a predetermined maximum time period responsive to successive actuations of said vehicle-actuated devices, said actuations being spaced from eachother a time period less than said minimum period. a

3. In a traffic-signaling system, the combination of a signal positioned at the intersection of several thoroughfares and operable to indicate the right of way to each of saidthoroughfares successively and simultaneously to indicate stop to the others, vehicle-actuated devices in each of said thoroughfares, relays responsive to actuations of said vehicle devices and operable to record the presence of vehicles at the intersection on thoroughfares not having the right of way, timing switches for each of said thoroughfares operable in response to the setting of said relays and a signal switch operated responsive to the joint action of said timing switches to energize said signal thereby to maintain a right of way on one thoroughfare for a predetermined minimum time period responsive to a single actuation of said vehicle-actua d 'evices and to extend said period to a predetermined maximum responsive to repeated actuation of said vehicle-actuated device.

4. In a trafiic-signaling system, the combination of a signal positioned at the intersection of two thoroughfares and operable to alternately indicate the right of way to each of said thoroughfares respectively while indicating stop to the other, vehicle-actuated devices in each of said thoroughfares, relays responsive to actuations of said vehicle devices in the thoroughfares respectively and operable to record the presence of vehicles at the intersection on the thoroughfares not having the right of way, a ti..1ing switch for each of said thoroughfares operable responsive to the settingof the relay corresponding to the vehicle-actuated device in one thoroughfare, anda signal switch operated responsive to the joint action of said timing switches to energize said signal to maintain the right of way on one thoroughfare for a predetermined minimum time period responsive to a single actuation of a said vehicle-actuated device in that thoroughfare and to transfer the control of said signal to the second of said timing switches at the end of this period.

' 5. Ina trailic-signaling system, the combination of a signal positioned at the intersection of several thoroughfares and operable to indicate the right of way to each of said thoroughfares in succession and simultaneously indicating stop to the others of said thoroughfares, vehicleactuated devices in each of said thoroughfares, a recording switch for each of said thoroughfares responsive to actuations of said vehicle devices in corresponding thoroughfares and operable to record the presence of vehicles at the intersection responsive to the momentary actuation by vehicles on the thoroughfare not having the right of way, a timing switch for each m said thoroughfares and responsive to actuatiort'v of said recordingrelay and operable at a predetermined speed for establishing operating circuits to a signal switch, a signal switch operable to energize said signals and connect it to said timing switches alternately during their respective operations, whereby said signal switch is maintained for a predetermined minimum period in one position responsive to a single actuation of a device in one of said thoroughfares and is maintained in another position for another predetermined minimum period responsive to an actuation of the vehicle device in another thoroughfare.

5. In a traflic-signaling system, the combination of a traflic signal located at the inte section of several thoroughfares, vehicle-actuated devices in each of said thoroughfares, relays responsive respectively to actuations of said devices, a timing switch for each thoroughfare and a signal switch, said signal switch controlling said signals to'grant the right of way to said thoroughfares responsive to operations of said devices and arranged to initiate the movement of the timing switch corresponding to the thoroughfare having the right of way. means controlled by said timing switch for locking said signal switch in its position for a predetermined minimum time period after which an actuation of the device in another thoroughfare may change the position of said signal switch to shift the right of way to that thoroughfare and simultaneously start a second timing switch.

I. In a traffic-signaling system, the combination of a signal located at the intersection of several thoroughfares, a switch for said signal to grant the right of way to thethoroughfares respectively, vehicle-actuated devices in each of said thoroughfares, relays operated by said devices to record the presence of vehicles, and a timing switch for each'of said thoroughfares, said timing switch being set into motion when the right of way is obtained by its corresponding thoroughfare in response to an operation of the said device and its corresponding relay in'said thoroughfare, said timing switch being provided' with means for maintaining its movement for a predetermined maximum time period and provided with means to intermittently release its corresponding relay during said maximum period whereby the right of way is maintained in said thoroughfare for a minimum time period in response to a single actuation of said relay and whereby said relay is periodically released for the purpose of enabling said devices and corresponding relay in another thoroughfare to obtain the right of way for said thoroughfare. 8. In a trafllc-signaling system, the tion of a signal, located at the intersection of several thoroughfares, a switch for setting said isignaltogranttherightofwaytothesaidthorcombin aoughfares respectively, means for operating said switch comprising vehicle-actuated devices in each of said thoroughfares-a relay corresponding to each of said" thoroughfares and operated to closed position by the said device in' the corresponding thoroughfare, a timing switch for .each of said thoroughfares, said timing switches being set into motion by said signal switch when the'right of way is granted thereby to the'thoroughfare corresponding to each of said timing switches, said timing switchesbeing provided with means for maintaining its motion for 'a'predetermined minimum time period, with means for intermittently releasing the relay corresponding to said thoroughfare and with means for operating' said signal control switch to return the rigtrt of way to the corresponding thoroughfare in case another thoroughfare is not using said right of way, whereby each of said thorough fares obtains the right of way for a minimum period for each vehicle passing thereover and whereby said right of way may be obtained for a maximum period in response to vehicles operating said device's at intervals smaller than said minimum time period and whereby the rightof way is automaticallychanged at the end of said periods in case a vehicle is waiting on another thoroughfare.

BENJAMIN W. JONES. 

